Solar panels appear to have cooling benefits. Just the add-on you would want when the sun is blazing down. In a new study, a team of researchers led by Jan Kleissl, a professor of environmental engineering at the UC San Diego Jacobs School of Engineering have found that that during the day, a building’s ceiling was 5 degrees Fahrenheit cooler under solar panels than under an exposed roof. Also at night, the panels help retain heat, thus reducing heating costs in the winter.
When we think of solar panels, we obviously miss these side benefits as we are more concerned with energy generation and efficiency. But the latest study tells us that infinitesimal and indirect benefits like these also have an impact on energy efficiency and a building’s total energy cost. The research team estimated that if one takes the energy benefit as money saved, then it’s nearly a 5 percent discount on the solar panels’ price, over the panels’ lifetime.
The study was conducted over three days in April on the roof of the Powell Structural Systems Laboratory at the Jacobs School of Engineering and recorded with a thermal infrared camera. The building has tilted solar panels and solar panels that are flush with the roof. Some portions of the roof are not covered by panels.
The panels act as roof shades and protect the rooftops from heating up from direct sun rays. Also the wind blowing between the narrow confines of the solar array take away some more heat. The study over three days estimated that the panels reduced the amount of heat reaching the roof by about 38 percent.
Kleissl said,” There are more efficient ways to passively cool buildings, such as reflective roof membranes. But, if you are considering installing solar photovoltaic, depending on your roof thermal properties, you can expect a large reduction in the amount of energy you use to cool your residence or business.”
Though the scope of the study was small, it could help homeowners calculate energy savings and costs while installing solar panels. With more funding, Kleissl said his team could develop a calculator that people could use to predict the cooling effect on their own roof and in their own area.
Image: Flickr (muenzer)
